1 | /* |
2 | * Copyright 2016-present Facebook, Inc. |
3 | * |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. |
6 | * You may obtain a copy of the License at |
7 | * |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * |
10 | * Unless required by applicable law or agreed to in writing, software |
11 | * distributed under the License is distributed on an "AS IS" BASIS, |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
13 | * See the License for the specific language governing permissions and |
14 | * limitations under the License. |
15 | */ |
16 | |
17 | #pragma once |
18 | |
19 | #include <folly/Portability.h> |
20 | |
21 | #include <cstdint> |
22 | |
23 | #ifdef _MSC_VER |
24 | #include <intrin.h> |
25 | #endif |
26 | |
27 | namespace folly { |
28 | inline void asm_volatile_memory() { |
29 | #if defined(__clang__) || defined(__GNUC__) |
30 | asm volatile("" : : : "memory" ); |
31 | #elif defined(_MSC_VER) |
32 | ::_ReadWriteBarrier(); |
33 | #endif |
34 | } |
35 | |
36 | inline void asm_volatile_pause() { |
37 | #if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64)) |
38 | ::_mm_pause(); |
39 | #elif defined(__i386__) || FOLLY_X64 |
40 | asm volatile("pause" ); |
41 | #elif FOLLY_AARCH64 || defined(__arm__) |
42 | asm volatile("yield" ); |
43 | #elif FOLLY_PPC64 |
44 | asm volatile("or 27,27,27" ); |
45 | #endif |
46 | } |
47 | } // namespace folly |
48 | |